Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 40 (10 October 2025)

Regional Situation: Influenza activity in the Americas remains low but shows an upward trend. At the regional level, RSV circulation is declining, while SARS-CoV-2 has increased in recent epidemiological weeks (EW), reaching a positivity rate of 9%. In North America, influenza activity remains at interseasonal levels. RSV circulation is low and stable, while SARS-CoV-2 is increasing, with a positivity rate of 10.7%. In the Caribbean, influenza circulation is decreasing, with a positivity rate of 6%, predominantly subtype A(H1N1)pdm09. RSV activity is increasing this EW, reaching a positivity rate of 10%, while SARS-CoV-2 circulation has declined to 4.9%. In Central America, influenza activity is decreasing, with a positivity rate of 5.6%. SARS-CoV-2 shows a slight increase this week (3.8% positivity), while RSV rises to a positivity rate of 17.6%. In the Andean subregion, influenza A activity has slightly increased to 5.4% positivity. RSV shows an increase this week (10.7% positivity), while SARS-CoV-2 has decreased compared to the previous week, reaching a positivity rate of 6.8%. In Brazil and the Southern Cone, influenza activity is increasing (5.1% positivity), with predominant circulation of influenza A(H3N2). RSV circulation has decreased compared to the previous EW, with a positivity rate of 3.4%, while SARS-CoV-2 remains at low levels but with an upward trend (5.9% positivity). The circulation of other respiratory viruses (ORVs) remains elevated and trending upward at the regional level, except in the Brazil and Southern Cone subregion.